<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    * {
      padding: 0;
      margin: 0;

    }
    .wrapper {
      width: 100px;
      height: 100px;
      border: 1px solid black;
      
    }
    .child {
      width: 40px;
      height: 50px;
      border: 1px solid black;
    }
    .child:nth-of-type(1) {
      float: left;
      background-color: red;
    }
    .child:nth-of-type(0n+2) {
      width: 70px;
      background-color: yellow;
    }
    .child:nth-of-type(3) {
      
    }
    .child2_child {
      width: 10px;
      height: 10px;
      background-color: black;
      display: inline-block;
    }
    
    
  </style>
</head>
<body>
  <div class="wrapper">
    <div class="child"></div>
    <div class="child">
      <div class="child2_child"></div>
    </div>
  </div>
  
</body>
</html>